System of electrical powee transmission



(No Model.) 8 Sheets-Sheet 1.

N. TBSLA. SYSTEM OF ELECTRICAL POWER TRANSMISSION.

No. 511,560. Patented Dec. 26, 1893.

(Zeneraiar (No Model.) 3 Sheets-Sheet 2. N. TESLA. SYSTEM OF ELECTRICALPOWER TRANSMISSION.

No. 511,560. Patented De0.'26, 1893.

defiant/02' if! D S p t a S Q I .9 J U WITNESSES 2 INVENTUH )fa vad ema, 14/6 Q ATTO R N EY (No Model.) 3 SheetS-Sheet 3.

N. TE-SLA.

SYSTEM OF ELECTRICAL POWER TRANSMISSION. No. 511,560. Patented Dec.26,1893.

WITNESSES INVENTOR ATTORNEYS.

we mwml. umouuml 0000A.

vluouawm u, 04

UNITED STATES PATENT OFFICE.

NIKOLA TESLA, CF NElV YORK, N. Y., ASSIGNOR TO THE TESLA ELECTRICCOMPANY, OF SAME PLACE.

SYSTEM OF ELECTRICAL POWER TRANSMISSION.

SPECIFICATION forming part of Letters Patent No. 511,560, dated December:26. 1893.

Application filed December 8, 1888. Serial N0.293,052. (No model.)

'l'o all whom, it may concern: or less extent than in the other. Thedistri- Be it known that I, NIKOLA TESLA, a subbution of themainororiginal currentthrough ject of the Emperor of Austria-Hungary, fromthe two motor circuits may be effected by in- Si11iljai1,Lika, bordercountryof Austria-Hunduction or by derivation. In other words, I gary,residing at New York, in the county may pass the alternating currentfrom the and State of New York, have invented cersource through oneenergizing circuit, and intain new and useful Improvements in Sysduce bysuch current a second current in the tems of Electrical PowerTransmission, of other energizing circuit. Or, on the other which thefollowing is a specification, referhand, I may connect up the twoenergizing 1o ence being had to the drawings accompanycircuits of themotor in derivation or multiing and forming a part of the same. ple arcwith the main circuit from the source.

In certain patents heretofore granted,I have In either eventI make dueprovision for mainshown and described a system of electrical taining adifference of phase between the ourpower transmission in which eachmotor conrents in the two circuits or branches.

i5 tained two or more independent energizing In an application filed byme May 15, 1888, circuits through which were caused to pass Serial No.273,993, Ihave shown and described alternating currents having in eachcircuit the means which I have employed for secursnch difference ofphase that by their coming this result by inducing one energizing binedor resultant action they produced a rocurrent from the other.

2o tary progression of the poles or points of man- My presentapplication relates to the means imum magnetic elfect of the motor andthereemployed when the two energizing currents by maintained therotation of its movable are obtained from a single original source byelement. In the system referred to and dederivation. scribed in the saidpatents the production or In explanation of what appears to be the 5 25generation of the alternating currents, upon principle of the operationof my invention the combined or resultant effect of whichthe and of thefunctions of the several instruoperation of the system depends, iseffected mentalities comprised thereby, let it be asby the employmentofan alternating current sumed that the two energizing circuits of angenerator with independent induced circuits alternating current motor,such, for example,

0 which, by reason of the winding or other 0011- as I have described inmy Patent No. 382,280,

struction of the generator, produces-currents dated May 1, 1888, areconnected up in deridiffering in phase, and these currents are convationor multiple arc with the conductors veyed directly from the generator tothe corof a circuit including an alternating current responding motorcoils by independent lines generator. It is obvious thatif both circuits8 5 or circuits. I have, however, discovered that are alike and otterthe same resistance to the I may produce the same or a similar resultpassage of the current no rotary effect will be by an alternatingcurrent from a single origiproduced, for although the periods of thecurnal source using between the generator and rents in both circuitswill lag or be retarded motors but one line or transmission circuit. toa certain extent with respect to an uno Broadly stated, this system ormethod inretarded current from the main circuit, their volves a sourceof alternating or equivalent phases will coincide. If, however, thecoils currents, a single transmission circuit, a moof one circuit have agreater number of contor having independent energizing circuitsvolutions around the cores, or a self induction connected with oradapted for connection coil be included in one of the circuits, the 9 55 with the transmission circuit, means for renphases of the current inthat circuit are redering the magnetic effects due to the enertarded bythe increased self induction. The gizing circuits of dilferent phase,and an ardegree of retardation may readily be secured mature within theinfluence of the energizby these means which will produce the difingcircuits; the means foraccomplishing this ference in electrical phasebetween the two I00 50 result being of such a nature as to retardthecurrents necessary for the practical operation current in one energizingcircuit toa greater of the motor. If in lieu of increasing the selfinduction of one circuit a dead resistance be inserted, the selfinduction of such circuit exerts a correspondingly diminished efiect,and the phases of the current flowing in that branch are brought morenearly in unison with those of an unretarded current from the main lineand the necessary difference of phase between the currents in the twoenergizing circuits thus secured. I take advantage of these results inseveral ways. For example, I may insert variable resistances in bothbranches or energizing circuits and by varying one or the other so as tobring the phases of the two currents more or less in unison with thoseof the unretarded current, I may thus vary the direction of the rotationof the motor. In lieu of resistances I may employ variable selfinduction coils, in both circuits. Or I may use a resistance in one anda self induction coil in the other and vary either or both. This systemor means of operating the motors is rendered of great practical value byemploying an armature wound with energizing coils closed uponthemselves, in which currents are induced by the alternating currentspassing in the field coils that serve to greatly increase the mutualattractive elfect between the armature and the field magnets. This useof the armature with closed coils I regard as an important feature of myinvention. These several features of the invention I shall now describemore in detail by reference to the accompanying drawings.

Figure 1 is a diagram of the system in which the motor coils orenergizing circuits are in derivation to the main line with a deadresistance inserted in one circuit. Fig. 2 is a diagram showing deadresistances in both motor circuits. Fig. 3 is a diagram showing a selfinduction coil in one motor circuit. Fig. t is a diagram showing a'deadresistance in one circuit and a self induction coil in the other. Fig. 5in like manner shows a self in; duction coil in each motor circuit. Fig.6 is a diagram showing the two motor circuits of different electricalcharacter. Fig. 7 is a diagram illustrating means for varying at willthe electrical character of the motor circuits.

Referring to Fig. 1, A designates a suitable source of alternatingcurrents and B B the line wires running therefrom. It will be understoodthat the generator A may be a primary or secondary generator, and theline B B may be the main transmission circuitor a local circuit from atransformer connected at any point in the line of a main or transmissioncircuit. For convenience in this case, it will be considered as a linefrom a given source of current to one or more motors. The motor containsa given number of pole pieces wound with two sets of coils O and D. Thearmature is wound with permanently closed energizing coils E in whichcurrents are developed by inductive action when the motor is inoperation which magnetize the armature core and greatly increase theefficiency of the motor. Assuming the two motor circuits to have thesame degree of self induction and resistance no rotary effect will beproduced by the passage through them of an alternating current from thesource A. But if in one of the motor circuits, as D, a deadpresistancerepresented by R be introduced, the self induction of that circuit orbranch is reduced and the phases of current therein retarded to acorrespondingly less extent. The relative degrees of retardation of thephases of the current in the two motor circuits with respect to those ofan unretarded current from the circuit B thus produced will set up arotation of the motor which may be practically utilized formany'purposes.

If, as in Fig. 2, a dead resistance R,-R' be introduced into each motorcircuit, no rotary effect will be produced as long as the resist ancesare equal, but by varying the resistance in one circuit the retardationof the current in that circuit will be varied, and corresponding effectsproduced. For example, a reduction of the resistance in one circuitimparts to the motor rotation in one direction while a reduction of theresistance in the other circuit will producev a rotation in the oppositedirection. By means of the two rosistances, therefore, capable ofvariation or of being bodily withdrawn from or inserted in the circuitsby any well known means, a perfect regulation of the motorsis secured.

In Fig. 3 the arrangement of all the parts is similar to that shown inFig. 1 except that a self induction coil as S is introduced into onebranch or energizing circuit of the motor. The effect of thus increasingthe self induction in one of the circuits is to retard the phases of thecurrent passing therein to a greater extent than in the other circuitand in this way to secure the necessary difference in phase between thetwo energizing currents to produce the rotation of the motor.

In Fig.4 a self induction coil S is included in one of the motorcircuitsand a dead resistance R in the other. The increased self induction inone circuit thus produced acts to increase the difference of phasebetween the current in such motor circuit and the unretarded current'inthe main line B. On the other hand, the introduction of the deadresistance in the other motor circuit reduces the retardation and bringsthe phases of the current therein more closely in accord with those ofthe unretarded current, thus producing a correspondingly greaterdi'fierence of phase between the two currents in the energizing circuits0 and D.

In Fig. 5, two self induction coils S, S are shown, one in each motor orenergizing circuit. One of these coils as S is much smaller than theother and has less self induction or counter electro motive force thanthe other, so that the phases of current will be retarded to a lessextent than in the other. The two self induction coils may be of thesame character or size if it is desired to use but one at ICC , atime'for the purpose of reversing the motor,

or if'thi'y be constructed in well known ways so that they may bevaried.

In Fig. 7 the usual means for varying the resistance or self-inductionof the motor circuits at will are indicated by the lever M sliding overa series of resistance plates, and by a core N which is adapted to bemoved in and out of the induction coil S.

Similar results may be secured by such a construction or organization ofthe motor as will yield the necessary diiferences of phase. For example,one set of energizing coils may be of finer wire than the other, or havea greater number of convolutions, or each circuit may contain the samenumber of convolutions, but composed of different conductors, as, forinstance, one of copper, the other of German silver. I have representedthis in Fig. 6, in which the coils O are indicated by closer lines thancoils D.

There are other ways of varying the retardation due to the selfinduction in the two energizing circuits. For example, the motor coilsmay be all alike, but those of one energizing circuit connected inparallel while the others are connected in series, or the connection ineach ellirgizing circuit may be alike, but the ":"currenti directedthrough them may be of "Q G,tfierent strength, as when one of the curemuis supplied from a source of higher electro-motive force.

In the above description I have referred mainly to motors with twoenergizing circuits, but it is evident that the invention appliesequally to those in which there are more than two of such circuits, theadaptation of the same being a matter well understood by those skilledin the art.

In using in the claims the term active resistance as applied to themotor circuits in this case, it will be understood that the term refersto the opposing or retarding force existing in the circuits to thepassage of the alternating currents. Thus, the two circuits may have thesame dead resistance, but different degrees of self induction.

What I claim as my invention is- 1. The combination with a source ofalternating currents, and a circuit from the same, of a motor havingindependent energizing circuits connected with the said circuit, and

means for rendering the magnetic elfects due to said energizing circuitsof dilferent phase and an armature within the influence of saidenergizing circuits.

2. The combination with a source of alternating currents and a circuitfrom the same, of a motorhaving independent energizing circuitsconnected in derivation or multiple arc with the said circuit, the motoror energizing circuits being of different electrical character wherebythe alternating currents therein will have a difference of phase, as setforth.

SJlhe combination with a source of alternating currents and a circuitfrom the same, of a motor-having independent energizing circuitsconnected in derivation or multiple arc with the said circuit and ofdifierent active resistance, as set forth.

4. In an alternating current motor, the combination with field magnets,of independent energizing circuits, adapted to be connected in multiplearc with the conductors of the line or transmission circuit and aresistance or self induction coil in one or both of the said motorcircuits, as set forth.

5. In an alternating current motor, the com bination with the fieldmagnets or cores of independent energizing coilsjilapted to be connectedin multiple arc withthe line or transmission circuit, and a variableresistance or self induction coil included in 01mm both of the motorcircuits as set forth.

6. In an alternating current motor, the combination with the fieldmagnets or cores and independent energizing circuits of different activeresistance and adapted to be connected with the line or transmissioncircuit, of an armature wound with closed energizing coils orconductors, as set forth.

7. The combination of a generator of alternating currents, a pair ofmains connected thereto, a multiple circuit differential phase, and anelectric motor having one circuit connected directly to said mains, andthe other circuit connected to said mains through an interposedelectro-motive phase-changing device adapted to change the time periodof the currents passing through it.

NIKOLA TESLA.

WVitnesses:

FRANK E. HARTLEY, FRANK B. MURPHY.

Correction in Letters PatentNo. 5H, 60,

It is hereby certified that in Letters Patent No. 511,560, grantedDecember 26, 1893, upon the application of Nik0la Tesla, of New York, N.Y., for an improvement in Systems of Electrical Power Transmission, anerror appears in the printed specifica tion requiring correction, asfollows: In line 95, page 3, the words and an should be stricken out;and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Oiiice.

Signed and sealed this 9th day of June, A. 1)., 1903.

[SEAL] F. I. ALLEN,

Commissioner of Patents.

